Ketamine would increase cerebral blood volume (CBV) through which mechanism?

Ketamine would increase cerebral blood volume (CBV) through which mechanism?

• A. Decreases cerebral blood flow (CBF)
• B. Augments CO2 responsiveness of the cerebral vasculature
• C. Reduces cerebral metabolic rate (CMR)
• D. Increases cerebral blood volume (CBV)

Answer: (D)

Ketamine raises cerebral blood flow and volume because it increases neuronal activity and metabolic demand in the brain. As metabolic requirement climbs, the vessels dilate to supply more blood (flow-metabolism coupling), so both cerebral blood flow and, consequently, cerebral blood volume rise. Among the given options, the direct description that matches this outcome is an increase in CBV. Lowering cerebral blood flow would not raise CBV, and reducing cerebral metabolic rate would not drive extra blood flow. Augmenting CO2 responsiveness could influence flow with changes in CO2, but the primary driver of the baseline CBV increase with ketamine is the rise in metabolic demand leading to increased CBV.

Ketamine raises cerebral blood flow and volume because it increases neuronal activity and metabolic demand in the brain. As metabolic requirement climbs, the vessels dilate to supply more blood (flow-metabolism coupling), so both cerebral blood flow and, consequently, cerebral blood volume rise. Among the given options, the direct description that matches this outcome is an increase in CBV. Lowering cerebral blood flow would not raise CBV, and reducing cerebral metabolic rate would not drive extra blood flow. Augmenting CO2 responsiveness could influence flow with changes in CO2, but the primary driver of the baseline CBV increase with ketamine is the rise in metabolic demand leading to increased CBV.